It is known to use Nitrogen PSA product gas or feed air when pressurised, to actuate the process valves of a PSA apparatus. The feed air supplied to a PSA plant from its normal dedicated compressor is typically saturated in both oil and water, or at least water if an oil free compressor is used. Product Nitrogen is often used as the actuator gas after the initial start up so as to avoid the problems associated with a saturated supply.
The above arrangement saves the cost of providing a separate supply of instrument air or the necessity to draw air from a separate factory supply. Both these alternatives would introduce extra cost and increase the likelihood of plant failures occurring.
With oxygen PSA systems, it is still possible to use the feed air supply with its inherent problems of saturated gas, however, for safety reasons the dry product gas cannot be used.
It is an object of the present invention to provide a means of providing a source of actuator gas to the process valves and instrumentation of a PSA apparatus which reduces and possibly eliminates the problems associated with the above mentioned arrangements. It can also be used with Nitrogen PSA system, saving the product gas. Fairly insignificant on large plants but a far greater percentage on small plants.